[Scip] Saving problem to .nl format produced by AMPL

[Stefan Vigerske]

Hi,

no, you need AMPL to produce a file in .nl format.
And AMPL needs AMPL .mod files as input, which SCIP cannot write either.

You could let SCIP write your PIP as .gms file, and then use GAMS to 
convert it to a .mod file. Or you can Ipopt via GAMS.
But all this requires a GAMS license.

If you write your .pip files by some program anyway, then you could 
probably modify it to write .mod files, too. Then with AMPL you could 
convert these into .nl files.
Or you could write .osil files, and use the OS/Ipopt interface to run 
Ipopt. That would be an all-open-source way to do it.

Stefan

On 06/24/2014 12:20 AM, Ramón Casero Cañas wrote:
> Dear all,
>
> Sorry for the sligh off-topic. I'd like to compare SCIP to ipopt solving a
> problem. I see that SCIP v 3.1.0 can save to formats
>
>   file reader          extension  description
>   -----------          ---------  -----------
>   ccgreader                  ccg  file writer for column connectivity graph
> file format
>   cipreader                  cip  file reader for CIP (Constraint Integer
> Program) format
>   fznreader                  fzn  file reader for FlatZinc format
>   gmsreader                  gms  file writer for MI(NL)(SOC)Ps in GAMS file
> format
>   lpreader                    lp  file reader for MIPs in IBM CPLEX's LP
> file format
>   mpsreader                  mps  file reader for MIQPs in IBM's
> Mathematical Programming System format
>   opbreader                  opb  file reader for pseudo-Boolean problem in
> opb format
>   pipreader                  pip  file reader for polynomial mixed-integer
> programs in PIP format
>   ppmreader                  ppm  file writer for portable pixmap file
> format (PPM), open with common graphic viewer programs (e.g. xview)
>   pbmreader                  pbm  file writer for portable bitmap file
> format (PBM), open with common graphic viewer programs (e.g. xview)
>   rlpreader                  rlp  file reader for MIPs in IBM CPLEX's RLP
> file format
>   wboreader                  wbo  file reader for pseudoboolean wbo file
> format
>
> but not to .nl, which is the format that the ipopt binary can load. Is
> there a way to produce an .nl file from the .pip file that I use to load
> the problem into SCIP?
>
> Best regards,
>
> Ramon.
>
>
>
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